Apparatus for mineral separation



Oct. 15, 1940. E. KREHER ET AL APPARATUS FOR MINERAL SEPARATION Filed Dec. 15, l 2 Sheets-Sheet 1 m in m v a v Q k\ x N N N M. N

AREHER BY c M you/v0 Oct. 15, 1940. KREHER AL 2,217,687

APPARATUS FOR MINERAL SEPARATION Filed Dec. 15, 1957 2 SheetsSheet 2 INVENTO g V E. KREHER K. KR HER BY C-M 00/1 6- Patented 0. 1. 15.1940

UNITED .STATES PATENT OFFICE APPARATUS FOR MINERAL SEPARATION Ernest Kreher and Karl Krehen Tanipa, and 7 Charles Mart Young, Miami, Fla.

Application December 13.1937, Serial No. 179,442

4 Claims.

An object of our invention is to provide a novel system and mechanism for the separation of gold and other valuable metals from the alluvial deposits in which they occur, hydraulically.

A still further object is to provide a more efficient system of mining in which the metal particles existing in alluvial and other like matrix may be carried by moving water into sump holes and then pumped, or pumped directly from the beds of streams, by one or more centrifugal pumps through a separator casing containing difiusing vanes and riflies which cause the gold to be deposited while the debris or tailing is carried through and discharged at a desired location.

A still further object is to provide a novel form of ore separator in which a series of difiusing vanes and riilles are employed to separate the valuable metal from the alluvial deposit.

A further object is to provide an enclosed casing about the separating members which scour and remove the metal and in which casing the metal is retained after its separation whereby access thereto by unauthorized persons and theft of the metal is prevented.

A still further object is to provide a separating apparatus which is inexpensive to construct, compact and of relatively small weight so that it is portable and may easily be transported to any inaccessible location which is rich in mineral deposits. Other and further objects will become apparent to those skilled in the art as the description of the invention proceeds. For a better understanding thereof, reference is made to the following description taken in connection with the accompanying drawings in which;

Fig. l is an elevation of the separator also showing the pump connected thereto,

Fig. 2 is a sectional view through the separator taken in a. plane normal to its length,

Fig. 3 is a vertical section of the inlet conduit,

Fig. 4 is a horizontal section of the approach conduit,

Fig. 5 is an enlarged sectional view of the riflle and baflle plates taken in a vertical plane passing through the axis of the separator and,

Fig. 6 is a sectional view showing the-shape of casing used in the construction of the centrifugal pump.

Referring first to Fig. 1, our invention is shown as comprising an alluvial separator I shown as a steel conduit of generally cylindrical shape and preferably made of three or more sections 2, each 4 feet long and electrically welded, flanged or riveted together at the joints 3. The separator is mounted for easy rotation on two pairs rollers 4, the rollers being mounted on a pair of skids 5.- This mounting arrangement makes the separator readily portable and easy to transport as asingle unit or in sections and the cost of removal from one site to another very small. Running along the upper half of the conduit and electrically welded to the inner wall thereof is a flat steel plate l which carries a series of flat steel deflecting or baflle plates 1 about 2 inches wide and each inclined at an angle of about 45 de- 10 grees to plate 6 as shown more clearly in Fig. 5. This construction results in a closed space being formed between plate 6 and the top of the conduit. Electrically welded to the inside of the conduit and running parallel to plate 6 are two steel retaining strips 8 which serve to hold the riffles 9 in position and which extend clear along the sides of the conduit.

Each riflle is preferably made of cast iron and comprises a substantially flat body portion I0 whose lower edge is curved to fit closely against the interior of the conduit and whose upper edge is straight. Projecting from the rear of body portion l0; and at right angles thereto, are two spacer webs II which are shaped as shown in Fig. 5 so that the rear, inclined edge l2 of each spacer web rests against the front face of the adjacent riiile. This construction serves to space the riflles 6 inches apart and to maintain them at an angle of approximately 45 degrees with respect to the shell I, as shown more clearly in Fig. 5. If desired, a wear plate l3 may be provided along each side of theshell, those shown consisting 'of long steel plates, 5 inches wide and having their lower and upper edges electrically welded to strips 8 and the inner surface of the conduit respectively. The function of these plates is to prevent wear on the interior surface of the conduit, the tailings striking and rubbing against the wear plates as they pass along 40 through the conduit. Additional riflies may be secured to the wear plates, if desired.

An outlet conduit l4 and an inlet conduit l5 are provided and secured in place at the two ends of the separator, the cross sectional areas of these conduits being substantially smaller than that of the separator, so that the velocity of the fluid is decreased considerably upon its entering the separator and it is increased again upon its entrance into the outlet conduit. The construction of conduits l4 and I5 is similar except that no deflecting plates are provided in outlet. it. As shown, conduit l5 terminates in a flange I6, which abuts against a flange I'I on the end of the separator and is secured thereto by a plurality of bolts 50. Flange It has a rectangular shaped opening I8, 20 inches wide and 11 inches high. Welded to flange it at the edges of this opening are the top and bottom walls i9 and 20 and side walls 2| and 22 of a generally rectangular shaped box, the sides of which are tapered toward the right to form an opening 8 inches square. The four sides of this box may be reinforced by having a plurality of thin steel strips 23 welded thereto at spaced intervals, as shown in Fig. 3. ,At its small end the box has a circular steel flange plate 2| welded thereto, plate 24 cooperating with a flange 25 to form a rotary joint of any known type, the details of which are not shown. Flange 25 is secured to the outlet pipe 26 of the centrifugal pump 21, the pump in this case having an outlet pipe 8 inches in diameter. Welded to the plates 2| and 22 are the spaced apart baiile or deflecting plates 28 arranged at an angle of approximately 45 degrees and extending the full width of plates 2| and 22. Bailie plates 28 are staggered along the sides 2| and 22,

being located at the intersections of the sides andthe dash line as shown in Fig. 4.

In order to remove the recovered metal from the separator, an opening is made in flange l6 and plate 22 and a short section of steel pipe 29 has one end cut to flt this opening and is electrically welded in the position shown in Fig. 4.

The outer end of pipe 29 has a circular annular flange 30 welded thereto and a suitable cover plate 3| secured to 30 as by a plurality of bolts 32 or other known fastening means. With cover plate 3| in position, it will be understood that water cannot escape from or through cleanout pipe 29 and any recovered metal which may be in the separator is completely enclosed and may not be easily stolen as is the case when the usual type of open riflle troughs are used.

According to our invention the alluvial deposit bearing the precious metal, for example, gold, platinum or tin in the form of powder and flne and larger sized fragments, is washed down one or more ditches 34 into a sump hole 35 into which the intake hose or pipe 36 of the centrifugal pump projects, power being supplied to the pump by an electric motor or equivalent power source. The outlet orifice of the pump is preferably connected to the short pipe 26 by a strong rubber hose 33 to provide a degree of flexibility at the inlet of the separator. The mixture of water and alluvial deposit is drawn up by the pump and discharged at a high velocity, for example, 10 to 20 feet per second through the outlet pipe 26 into the small and of inlet conduit l5. As the mixture passes through conduit l5, its velocity decreases steadily and the -matrix is caused to strike against the sides thereof by the battle plates 28, many of its particles also striking these plates. This action washes and scours the matrix particles and is effective in washing away the fllm of dirt which encloses many of the particles of metal. This removal of the lighter material adhering to the metallic particles assists in the later separation and recovery of the latter in the separator.

The effective area of the separator being substantially greater than that of conduit IS, the velocity of the mixture is further reduced in the separator to from 5 to 10 feet per second, a velocity of flowof 5.5 feet per second through the separator having been found very effective. As the mixture passes along through the separator the heavy metal particles settle down in the spaces between the riflles U under the action of gravity, their specific gravity being much higher than unity. Downwardly directed currents and increased turbulence caused by the baffle plates 1 also carry the metal particles into the spaces between the riiiles 9. According to our invention a still third and novel action causes the metal particles to settle into the areas of least disturbance which are located just at the rear of flat plates it. Such an area is indicated in Fig. 5 by 31. Consider a metal particle on the front face of plate [0. Gravity will not only cause it to pass down to the bottom of this plate and onto the interior surface 38 of the bottom of the separator, but also cause it to move forward along surface 88 into the quiet area 31, since the inclination of the separator and surface 38 is in this direction. In other words gravity assists in moving the heavy metal particles into the portions of the stream where the least disturbance exists. We prefer to operate the separator inclined upwards at an angle of from 5 to 30 degrees in order to secure this extra beneflcial action from the force of gravity but it will be understood that the invention is not so limited and our improved separator may be operated in a level or declining position. With the separator inclined upwardly at an angle of substantially 10 degrees, it was found that substantially all the metal settled within the .flrst six feet at the inlet end, so that a separator made up of three sections, each four feet long, is sufficient for certain types of alluvial deposit. For other deposits and metals we may, however, provide an additional number of sections as required.

As the metal accumulates in the spaces between the riflles, it displaces any sand or gravel therein and forces them upwards into the rapidly moving stream, which carries them along toward the outlet. Gravel and stones are prevented from piling up into mounds between the rifl'les, since such mounds projecting into the separator would decrease its effective cross sectional area. and hence increase the velocity of fluid flow therethrough. This increased velocity will carry the projecting stones onward toward the outlet. Upon reaching the outlet conduit H the velocity of the stream again increases as it passes therethrough and in the discharge pipe 39 the same velocity as in the inlet pipe 26 is reached. The residue may be discharged into a desired site directly from pipe 39 or it may be conveyed to a site at a distant location through a pipe line in which one or more booster pumps may be connected to maintain a high velocity of flow.

After operation for a desired period such as 24 hours, and a quantity of metal is in the separator, this may be easily removed by rotating it 180 degrees when the debris and metal will fall onto plate 6 and the debris will be washed out by the stream of water from the pump. This cleaning out process may be repeated, if required. The separator is then rotated another 90 degrees into such position that pipe 29 is at its lowest position. Cover plate 3| is then removed and a stream of water played into the separator from a hose or pipe inserted into pipe 39 when the recovered metal will be washed out from between the rimes and pass down the smooth interior surface of the separator into pipe 29 where it is discharged. In this washing out of the recovered metal, the inclination of the separator towards the inlet end, assists greatly in its transfer through the separator.

Any suitable means, either hand or power operated, may be used to rotate the separator on the rollers 4. That shown in Fig. 2 comprises a winch or capstan 4i mounted in bearings on a supporting block or pedestal 40 secured to an extension of one of the skids 5. A flexible cable or belt 43 has several turns passed around the winch drum and one or more turns passed around the separator. A suitable crank or handle 42 serves to rotate the winch. Or, a spur gear and pinion drive may be used instead.

In order to permit ready inspection of the amount of recovered metal in the separator at any time, a section thereof extending over 90 degrees or more may be cut out of the bottom near the inlet end and replaced by a similar shaped plate of glass or other transparent material. Such a glass window is indicated at 44, suitable known fastening means (not shown) being em.- ployed to secure the window in position. Also instead of, or in addition to the riflles heretofore described, a series of poles or steel rails may extend along the separator in the direction of its length.

As shown in Fig. 6, the impeller 46 of the centrifugal pump 21 rotates within a casing or shell whose inlet is at 48, the outlet not being shown. As clearly shown, the cross section formed by the outer ring 49 and sides 41 of the shell, is rectangular in shape.

As compared to other systems of mining, our system presents the following advantages;

1. It makes commercially valuable large areas of alluvial deposits which were valueless heretofore.

2. It renders the separator readily portable.

3. It makes possible the separation of gold and other valuable metals when ap'ump of the correct shape is used. The rectangular shaped pump shell throws the water and matrix mixture out radially in a straight stream, whereas a pump having the usual arch shaped shell, causes a spiral motion from each side of the pump toward the top of the arch causing the heavier solid bodies to strike against each other and thus reduce the velocity of flow.

4. It reduces very substantially the cost of the riiliing outfit.

5. It makes it possible to mine the matrix, separate the metals from it and discharge the matrix residue at almost any desired location and all in one continuous operation by means of centrifugal pumping.

6. It scrubs and cleanses the desired metal by the rapidly moving water. and by contact of the particles with the rapidly moving impeller blades of the pump, the bafiie plates of the inlet conduit and separator and also the riflles.

'7. It keeps the recovered metal enclosed, thus protecting it against theft.

8. It makes it possible to carry thedebris to almost any desired location by installing one or more booster pumps in the outlet pipe, if one pump does not carry it far enough. a

9. It makes possible the easy inspection of the recovered metals through the transparent section or sections in the bottom of the separator.

10. It saves time and much labor, increasing production to a marked degree and thereby greatly decreasing the cost of mining.

11. It provides an easy and quick means for cleaning out the separator hydraulically and also for removing the, recovered metals therefrom.

12. Its circular shaped casing is much more portable than the present fiat trough rifile boxes and the recovered metals are much more easily gathered from it.

13. It does not require the pumping of the matrix to a high elevation from which it runs over the riffles by gravity, thereby effecting a large saving in power and cost of equipment.

14. It provides a forced rifiie action in a confined space whereby clogging up of the riilies with matrix residue is prevented and a complete recovery of the metals in a short length of separator is possible.

15. It makes frequent, periodic removal of the recovered metals easy and inexpensive whereby accurate information as to their value is available at all times.

While we have indicated and described an arrangement for carrying our invention into effect, it will be apparent to one skilled in the art that the invention is by no means limited to the particular organization shown and described, but that many modifications may be employed without departing from the scope of the invention as set forth in the following claims.

We claim:

1. A mineral separator comprising in combination, a substantially long, cylindrical casing having inlet and outlet openings at its opposite ends, a horizontal plate extending lengthwise within said casing and secured to the walls thereof at its opposite sides, a plurality of downwardly directed baiiie plates extending crosswise of said I casing and secured to the bottom of said plate 'at spaced apart points, and a plurality of rifiies arranged at spaced apart points along the bottom of said casing, each of said riflies comprising a substantially plane plate having its lower edge shaped to conform to the interior surface of said casing and its upper edge substantially straight.

2. The arrangement of claim 1 in which each riflle plate is provided with two ofiset portions arranged at substantially 90 degrees thereto and adapted to engage the next adjacent riilie plate and thereby insure the desired spacing apart of the riflle plates.

3. A mineral separator comprising in combination, a closed casing having a curved bottom wall and being provided with inlet and outlet openings at its opposite ends, and a series of riflles disposed along the bottom of said casing, each riffle comprising a substantially flat plate whose loweredge is curved to conform to the bottom wall of the casing and a plurality of spacer webs projecting from the rear surface of said fiat plate and whose rear ends are inclined so as to seat against the front face of the next adjacent riflle and-maintain the flat plates of the series the riiiles in position within said casing.

CHARLES MARR YOUNG. KARL KREHER. ERNEST KREHER. 

